The present disclosure relates to surfaces and coatings for flash atomization, and more particularly, relates to incorporating enhanced surface technologies to improve flash atomization.
Atomization generally refers to the conversion of bulk liquid into a spray or mist (i.e. collection of drops), often by passing the liquid through a nozzle. An atomizer is an apparatus for achieving atomization. Common examples of atomization systems can include: gas turbines, carburetors, airbrushes, misters, spray bottles, and the like. In internal combustion engines for example, fine-grained fuel atomization can be instrumental to efficient combustion.
Current air-blast atomizers spread liquid from a nozzle orifice into a film on one or more pre-filming regions. The atomizers can use pressure, airflow, electrostatic, ultrasonic, and other like methods to create instabilities in the bulk liquid film to form droplets. Flash atomizers have been shown to produce very small droplets of uniform size, typically ranging from about 5 to about 300 micrometers. The droplet size is small for the flash vaporizer because enough vapor is generated in a channel, or orifice in the case of a cylindrical atomizer, to form a two-phase flow prior to injection of the fluid into a low pressure ambient environment. Typically, the surface of the channel is substantially smooth. The flash evaporation occurs when a subcooled liquid at high pressure flows into the pressure-reducing channel. The vapor is produced on the channel surface when the liquid temperature is high enough above the local bubble point (i.e., incipient superheat) that heterogeneous nucleation can occur on the channel surface. A two-phase fluid occurs as a result.
The flash atomization process, however, requires heating and pressurizing of the fluid upstream of the channel, in order to generate vapor in the channel required to form the two-phase flow. The heat and pressure required to flash vaporize the fluid can be very high for a given application, which can be costly, from both an operating and equipment standpoint. Reducing the fluid heating and high pressure pumping demands could significantly reduce operating costs and improve flash atomization performance.